Hydraulic flash welder control



Aug. 31, 1954 DQUTT 2,688,066

HYDRAULIC FLASH WELDER CONTROL Filed July 22, 1953 3 Sheets-Sheet l IN V EN TOR. m nysle v 001/52 BY 11 ig/2N5) Aug. 31, 1954 K. A. DOUTT HYDRAULIC FLASH WELDER CONTROL 5 Sheets-Sheet 2 Filed July 22, 1953 INVENTOR. lV/nys/ey 00a HTTOR Y Aug. 31, 1954 K. A. DOUTT HYDRAULIC FLASH WELDER CONTROL 3 Sheets-Sheet 3 Filed July 22, 1953 m m m w,

f (l'nysley A 000 477' RIVE) Patented Aug. 31, 1954 UNITED STATES i ATENT OFFICE 5 Claims. 1

This invention relates to electric welding apparatus and more particularly to an improved apparatus for imparting controlled movement to the movable platen of a flash welding machine.

Flash welding machines as known in the art comprise essentially an insulated normally fixed platen having an electrode and means to secure a workpiece thereto. A movable platen is also provided and includes an electrode and workpiece securing means. The movable platen is arranged for sliding movement toward and away from the fixed platen and means is provided for imparting such movement thereto. In the present disclosure at least one hydraulic cylinder and piston assembly is provided, the piston being connected to the movable platen.

In order that a controlled volume of hydraulic fluid may be supplied to the piston and cylinder assembly utilized, various types of valves and valve controlling means have been heretofore proposed and used. Such devices have generally had in common a mechanical connection with the movable platen of the flash welding machine so that the valves or other devices controlling and. moving the movable platen were in turn controlled by the position of the movable platen itself and/ or the speed of travel thereof. Those skilled in the art recognize that such dependency of the controlling elements of a flash welding machine is subject to variation depending upon the characteristics of the platen and workpiece, etc., to the end that an unequal and often undesirable action follows which results in an unsatisfactory weld.

Those skilled in the art are also aware that an improved welding technique will result from a desirably controlled and time flash welding operation and it is, therefore, a principal object of this invention to provide a hydraulic flash welder control operating to impart a most desirable welding cycle movement and control to the movable platen of the flash welding machine regardless of variations in the hydraulic pressure utilized, conditions effecting the movable platen and variations in the workpieces as to size, thickness, material, shape, etc.

A further object of the invention is the provision of a hydraulic flash welding control for a flash welding machine arranged to perform a complete welding cycle from flashing to upsetting with no hesitation in the controlled and timed advance of the movable platen and operating in effect to superimpose upsetting action on a continuing flashing action.

Those skilled in the art will recognize that flash Qil welder controls as heretofore known in the art had a common weakness in controlling the moticn of the movable platen of the flash welding machine in the welding cycle, particularly in that hesitancy in the forward progressive motion of the movable platen frequently resulted in no weld or a poor weld due to instantaneous oxidation of various metals occurring at the time of hesitation or momentary interruption between the flashing and upsetting action in the flash welding machine. Th present invention enables a continuous performance cycle and thereby eliminates completely the possibility of no welds or poor welds due to such oxidation.

A still further object of the invention is the provision or" an improved apparatus for imparting controlled movement to the movable platen of a flash welding machine and which apparatus produces a flashing cycle in accordance with its preset controls and superimposes an upset cycle on the flashing cycle, the movement of the platen during the flashing cycle being responsive only to the apparatus and the upset cycle being responsive to the position of the platen and workpieces.

A still further object of the invention is the provision of a control system for a flash welder as above outlined which facilitates and simplifies the setting up of the welding machine to perform a particular welding operation and the apparatus therefore includes means for readily changing the pattern of movement of the platen during flashing and, in accordance with a preferred embodiment of the invention, the same is accomplished by employing a simple and positive valve actuated control of the apparatus incorporating relatively movable valve members enabling various desired settings to be readily achieved.

A still further object of the invention is the attainment of a wider diversity and greater accuracy in the control of the variables making up a flash welding operation. For example, the pattern of the rate of change of the movable platen during the flashing action may be readily varied with respect to time and the interval between the initiation of flashing and the start of the upsetting. Such variable factors enable a much higher degree of control over the welding operation to be achieved and thereby contribute substantially to the quality of the Work performed.

A still further object of the invention is the provision of a hydraulic welder control which faciiitates and simplifies the setting up of the welding machine to perform a particular welding operation especially when the operation is to be repeated under automatic control. The invention, therefore, includes means for readily changing the pattern of movement of the movable platen during the flashing and upsetting portions of the welding cycle, the device being so arranged that regardless of the adjustments made, a complete cycling of the flash welding machine always occurs.

A still further object of the invention is the provision of a hydraulic flash welding control mechanism enabling a flash welding operation to start instantaneously and particularly with respect to the immediate movement of the movable platen of the flash welding machine.

A still further object of the invention is the provision of a hydraulic flash welding control mechanism for a flash welding machine which will impart immediate and smooth action to the movable platen of the flash welding machine and continue such smooth progressive movement of the movable platen in accordance with a predetermined flashing and upsetting cycle whether or not the movable platen is dry or lubricated and regardless of the weight, shape, material or other characteristics of the workpiece to the end that a perfect flash weld is obtained.

A still further object of the invention is the provision of a hydraulic flash welding control mechanism providing an adjustable starting velocity enabling the mechanism to be readily set to match the characteristics of various metals being welded.

A still further object of the invention is the provision of a hydraulic flash welding control mechanism that will automatically weld parts of unequal length which must have the same finished length.

A still further object of the invention is the provision of a hydraulic flash welding control mechanism that eliminates the need of a skilled operator as the device automatically provides for moving th pieces to be welded together from an uneven gap at a proper speed for proper flashing and welding.

A still further object of the invention is the provision of a hydraulic flash welding control mechanism that will control the platen position. of a flash welding machine without mechanical stops as heretofore believed necessary.

The hydraulic flash welding control mechanism disclosed herein comprises an improvement over the mechanism shown in my co-pending patent application Serial No. 189,835 filed October 12, 1950, now U. S. Patent 2,640,134 dated May 26, 1953, the primary improvement comprising the elimination of the connecting linkage which I heretofore believed necessary to position the sleeve of the valve with respect to the spindle thereof and the substitution of a hydraulically actuated, more readily controlled device for more advantageously imparting movement to the sleeve of the valve.

A still further object of the invention is the provision of a hydraulic flash welding control mechanism that is particularly advantageously employed in Welding strip steel sections to one another in a steel mill and wherein the area of the metal to be welded varies as well as the spacing between the sections to be welded and which operation must be efliciently done to not interfere with the further processing of the strip.

Those skilled in the art will recognize that it has heretofore been the practice in such operations to manually control the platen movement to bring the ends of the strip sections to be welded.

4 to position closely approximating the starting position of the flashing portion of the welding cycle, which operation required a skilled operator and consumed considerable valuable time.

The present apparatus automatically and rapidly moves the platens and hence the strips to be welded to one another to proper flashing position and automatically starts the flashing operation regardless of the gap between the workpieces. The ability of the mechanism to accomplish this action results in the starting of the flashing cycle at proper platen speed and thereby insures the successful weld of the parts as the flashing cycle is properly timed and achieves its intended purpose prior to the upset and welding portions of the complete welding cycle.

With the foregoing and other objects in view which will appear as the description proceeds, the invention resides in the combination and arrangement of parts and in the details of construction hereinafter described and claimed, it being the intention to cover all changes and modifications of the example of the invention herein chosen for purposes of the disclosure, which do not constitute departures from the spirit and scope of the invention.

The invention is illustrated in the accompanying drawing, wherein:

Figure 1 is a schematic diagram of the hydraulic flash welder control apparatus.

Figure 2 is a top plan view of a portion of the apparatus shown in Figure 1.

Figure 3 is an end elevation of the portion of the apparatus shown in Figure 2..

Figure 4 is a vertical section taken on line 1-5 of Figure 2.

By referring to the drawings and Figure 1 in particular it will be seen that a hydraulic flash welder control is disclosed and that the same may be formed as a compact assembled unit including the control apparatus and the hydraulic fluid supply for the flash welding machine and that the complete hydraulic flash welder control can be connected with any flash welder to suitably operate the movable platen thereof to perform an improved flashing and upsetting welding cycle. Specifically, in Figure l of the drawings the numeral it indicates a tank which actually forms a supporting base for the remainder of the apparatus and provided with projecting feet ill| so that the same may be attached to a flash Welding machine or positioned in proximity thereto. The tank it comprises a reservoir for the hydraulic fluid utilized and a filter i2 is disposed in the tank l0 and connected with the outlet orifice 13 thereof which in turn is in direct communication with a pump i l. The inlet orifice of the pum is is indicated by the numeral l5 and the outlet orifice is indicated by the numeral IS. The

pump id is driven by an electric motor ll which is connected to the pump it by means of a coupl ng it. A relief valve it having a pressure gauge 2d receives the hydraulic fluid from the pump I4 as the same is in communication with the outlet oriflce id of the pump M.

A fluid supply line 21 connects with the relief valve [9 and with the controlling apparatus hereinafter described. The pressure relief valve is arranged so that at such time as the flash welding machine is inoperative, hydraulic fluid from the pump i l is lay-passed through an oil cooler 22 which is connected with the relief valve l9 by means of a tubular fitting 23 and with the tank I G by means of a tubular fitting 26.

At such time as a flash weldin machine controlled by the hydraulic flash welder control disclosed herein is in operation, as, for example, a flashing and upsetting cycle, hydraulic fluid flows from the relief valve l9 through the fluid supply line 2! directly to an accumulator 25 Which is preferably of the air bladder type and to a high pressure inlet port 26 on a flashing and upset control valve A check valve 23 is positioned the fluid supply line 21 between the relief valve i9 and the accumulator 25 and permits fluid flow only toward the accumulator and the flashing and upset control valve 27.

Still referring to Figure 1 of the drawings it will be observed that the fluid supply line 2! includes a T 29, a portion of which communicates by way of a normally closed valve 35 with the tank In and which valve 30 is provided to permit the accumulator 25 to be drained. A second T 3| in the fluid supp-1y line 2| connects with a pressure reducing valve 32. A supply line 33 conveys hydraulic fluid at reduced pressure from the pressure reducing valve 32 to two low pressure supply lines 34 and 35 communicating respectively with a sequence starting valve 36 positioned above the flashing and. upset control valve 21 and with an upset pilot valve 37 which is disposed beneath the flashing and upset control valve 21.

Positioned adjacent the sequence starting valve 3'5 there is a flash control valve 38 including a reciprocally positioned piston 39, an end ll! of which extends outwardly of the ends of the flash control valve 33 and the left hand end of which (as best illustrated in Figures 2 and 4 of the drawings) is pivotally connected to a link ll which in turn is pivotally connected to a cam arm The sequence starting valve 36 and the flash control valve 35 are integrally formed. It will be observed that ports A and B in the sequence starting valve are in communication with ports A and B in the flashing and upset control valve 2? which is shown in vertical section in Figures 1 and 4 of the drawings and in communication with the upset pilot valve 3'! which is directly connected thereto.

It will thus be seen that fluid pressure from the pump it and the accumulator 25 flows by way of the fluid supply line 2| directly to the inlet port 25 in the flashing and upset control valve 2'! where it is controlled with respect to communication with a hydraulic cylinder 43. An outlet port i -l in the flashing and upset control valve 21 is connected by means of a fluid supply line 65 with the closed end of the hydraulic cylinder 43. A piston 35 is positioned within the cylinder 43 and a connecting rod 4'! extends outwardly through the opposite end of the cylinder 43 and connects with a movable platen 48 of the welding apparatus. A return fluid line 59 establishes communication with the rod end of the cylinder 43 and with a port 58 in the flashing and upset control valve 2?.

In Figures 2 and 4 of the drawings the cam arm 42 is shown connected with a cam 51 so that movement imparted to the cam arm 42 through the link 3! by the piston 40 in the flash control valve and piston 58 may be imparted to a spool 52 forming the multiple valve element in the flashing and upset control valve 27, as best illustrated in Figures 1 and 4 of the drawings.

Still referring to Figures 1 and 4 of the drawings it will be seen that the spool 52 is reciprocally positioned in a sleeve 53 which in turn is reciprocally positioned in the body of the flashing and upset control valve 21. A plurality of slot-like ports are formed in the sleeve 53 for registry with a plurality of ports in the body of the valve 21 and more particularly with a hardened tubular insert positioned therein and defining the actual orifices, as hereinafter described. The spool 52 is spring urged toward the left as shown in Figures 1 and 4 of the drawings by a coil spring 55 positioned in the right hand end of the sleeve 53 and the outermost left hand end of the spool 52 is provided with a rotor 55 engaging the cam 5i. The right hand end of the sleeve 53, as shown in Figures 1, 2 and 4, is connected with a driving piston 55 by means of a pin 52 which is positioned through registering transversely formed openings in the adjacent ends of the sleeve 53 and the driving piston 55. The driving piston 56 is positioned within an axial extension 58 of the flashing and upset control valve 2i and in turn carries a head 55 on its outer end. A piston rod 50 extends from the driving piston 55 outwardly through the head 59 and through the end portion thereof and terminates in a threaded section 6| which is threadably received in an adjustment nut 52.

A secondary adjustment nut 63 is threadably engaged in a threaded axial opening within the end of the piston rod 59. It will be observed that by rotating the adjustment nut 52 on the threaded section iii of the piston rod 55, the relative position of the piston rod 63 and hence the driving rod 56 and the sleeve 53 may be controlled with respect to maximum inward travel of he sleeve 53 to the left as shown in Figures 1 and 4 of the drawings.

A secondary spring 65 positioned within the head 59 and abutting a shoulder thereon on one side and the piston 56 on the other normally biases the piston 56 and hence the sleeve 53 inwardly of the valve or to the left as shown in Figures 1 and 4 of the drawings.

The extension 58 on the valve 21 also carries a sleeve positioning valve 65 which comprises a double solenoid actuated four-way valve normally spring centered to fully closed position which acts to control the flow of hydraulic fluid to and from the areas on either side of the piston 53 in the extension 58 of the valve 21. When the sleeve positioning valve 65 is actuated to introduce hydraulic fluid into the area on the left hand side of the piston 53 as by way of passageways 66 therein, the resulting action will be to move the piston 58 to the extreme right of the extension 58 and hence move the sleeve 53 to the right as shown in Figures 1 and 4 of the drawings. This initially positions the sleeve 53 so that upon the actuation of the upset pilot valve 31 hydraulic fluid flows from the supply line 35 through appropriate ports in the upset control valve 2? to move the spool 52 to the right which directs hydraulic fluid to the platen moving cylinder by way of the fluid supply line at, the amount of fluid delivered comprising between one-third to 40% of the total flow possible which acts to impart upset velocity to the piston 48 in the cylinder :3 and hence rapidly moves the platen 43 or other workpiece to flashing position. The upset pilot valve 31 comprises a solenoid operated valve as best illustrated in Figure 1 of the drawings.

By referring now to Figure 1 of the drawings it will be seen that a composite View of the flash welding control apparatus is disclosed complete with interconnecting piping. The view includes a horizontal section through the flash control valve 38 and the appended sequence starting valve 35 and a vertical section through the flashing and upset control valve 21 and its appended upset pilot valve 31.

It is believed that from the foregoing one skilled in the art will observe that the flash welding control apparatus comprises essentially the flashing and upset control valve 21 which directly controls the hydraulic fluid delivered by the pump it and the accumulator 25 to the platen moving piston and cylinder 46 and 43, respectively, the action of the flashing and upset control valve 2? being responsive to the operation of the piston is in the flash control valve 38, which is in turn responsive to the sequence starting valve 36 and the sleeve positioning valve 65 as hereinafter described. The movement of the piston ill in the flash control valve 38 imparts predetermined movement to the cam i and hence the spool 52 of the flashing and upset control valve 2'5.

Assuming that the workpieces to be welded (not shown) have been secured in the stationary and movable platens of the flash welder control by the device and that the pump I4 is being operated by the motor ii and hydraulic fluid is therefore being supplied the fluid supply lines 2!, 33, 3d and 35, the operating cycle of the flash welding machine is initiated by the manual or automatic closing of a switch 68.

Closing the switch 88 closes a circuit and conductor 69 and first energizes the sleeve positioning valve 155 to move the sleeve 53 to the right, as shown in Figures 1 and 4 of the drawings and subsequently energizes the upset pilot valve 31. The hereinbeiore described action of the hydraulic fluid moves the spool 52 to open a passageway between the inlet pipe 26 and the outlet pipe 35 whereby hydraulic fluid flows to the platen moving piston and cylinder assembly at and d3, respectively. As the platen moving piston 36 moves, it engages a limit switch 'iil which opens the switch 68, de-energizing the sleeve positioning valve 65 and the upset pilot valve 31 and a closes a circuit and energizes a solenoid F2 to activate the sequence starting valve 36 whereupon hydraulic fluid moves the piston 39 and hence imparts movement to the cam 51, as heretofore described, and moves the spool 52 toward the right in controlled, progressively increasing flashing velocity as determined by the cam 51.

It will occur to those skilled in the art that the cam Ed is adjustably mounted on the cam arm 52 so that it may be predetermined as follows: the slowest rising curve being obtained when the cam 5! is rotated clockwise to the end of its adjustment. The greatest platen acceleration is obtained with the cam rotated to its full counterclockwise position.

A piston valve E3 in the sequence starting valve 35 is normally biased to closed position by a coil spring i i located adjacent one end of the piston valve 73;. Motion of the solenoid 12 moves the piston valve 713 to the right, compresses the spring i l and opens a fluid passageway from an inlet port 15 which is in communication with the hydraulic fluid supply line 34 and establishes communication with a channel H. The channel ll is under the control of a variable flow control valve 78.

The channel ll communicates with the right hand portion of the flash control valve 38, and, responsive to the introduction of hydraulic fluid thereinto, the piston lit in the flash control valve 38 will move to the left. The left end of the 8. piston 40 is connected by means of the link 4! with the cam arm 52 heretofore referred to and the cam 5! is thus moved responsive to the motion of the piston ll]. The flow control valve 18 controls the amount of fluid delivered to the flash control valve 38 and hence controls the rate of travel of the piston 40 and hence the movement of the cam 51.

The flow control valve '18 is a metering valve and, as may be seen by referring to Figure 2 of the drawings, is provided with a manually adjustable control lever 83 by means of which the metering action of the flow control valve "58 may be controlled and preset. It will thus be seen that the sole function of the flash control valve 33 and its appended sequence starting valve 38 is to impart controlled mechanical motion to thecam 5! which in turn moves the spool 52 of the flashing and upset control valve Zl. The flashing and upset control valve 2i and its appended upset pilot valve 3'i control the actual hydraulic fluid delivered to the cylinder 3 for actuating the piston it which is connected with the movable platen 48 of the flash welder as heretofore described.

Still referring to Figure l of the drawings it will be seen that the fluid supply line 2! conveys hydraulic fluid to the inlet port 26 of the flashing and upset control valve 2'1! which communicates with an annular chamber 3i formed about the sleeve 53 by a cylindrical body member 82 which has spaced annular channels formed on its innermost surface and apertures communicating with said channels.

Hydraulic fluid introduced into the channel 8! (which comprises one of the annular channels in the cylindrical body member 62) thereby completely encircles the sleeve 53 and one or more apertures 83 in the sleeve are provided to convey the hydraulic fluid to the chamber within the sleeve and between a pair of spaced tapered heads 8d and 85 on the spool 52. As the spool 52 is moved'to the right by the cam 5!, as heretofore described, the head 35 will expose one or more orifices 86 in the sleeve 53. The orifice as establishes communication with an annular channel 87 in the cylindrical body member 82. The annular channel 3'5 is in communication with the outlet port d4 of the flashing and upset control valve 27. The fluid supply line 55 connects the outlet id with the closed end of the cylinder 43 so that hydraulic fluid is delivered to the cylinder is and moves the piston t6 and hence the movable platen 33 of the flash Welding apparatus. I

It will be observed that the head 85 on the spool 52 is provided with oppositely disposed tapers at diflerent angles on its opposite sides so that a metering action is had with respect to the delivery of hydraulic fluid to the aperture 86 with the result that the movement imparted to the movable platen is is always smooth. It will also be seen that the position of the sleeve 53 meters the fluid delivered to the cylinder 53.

Simultaneously with the delivery of hydraulic fluid to the cylinder 53 and the movement of the platen 48 by the piston 46, as just described, the head 84 on the spool 52 moves to open an aperture 83 in the sleeve 53 which communicates with an annular chamber 89 in the cylindrical body member 82. The annular chamber 89 communicates with the inlet port 58 and the return fluid line 49 establishes communication between the inlet port as and the opposite end of the cylinder 43 so that hydraulic fluid therein and being discharged therefrom through the return fluid line 49 is gradually admitted to the chamber within the sleeve 53 and to the left of the head 84 by the metering action of the tapered head 84. The hydraulic fluid thus admitted flows through one or more apertures St in the sleeve 53 into an annular chamber 9! formed in the cylindrical body member 92 which communicates with an outlet port 92. A return line 93 establishes communication between the outlet port 92 and the tank l so that the hydraulic fluid is thus delivered thereto.

Still referring to Figure 1 of the drawings it will be observed that the piston 46 and the movable platen ll) will move to the right responsive to the admission of hydraulic fluid to the cylinder 43 under the predetermined control of the flashing and upset control valve 21, it being observed that the relative movement of the spool 52 carrying the heads 8t and 85 with respect to the sleeve 53 is controlled by the cam heretofore disclosed and described whereby a desirable flashing curve or progressive motion of the movable plate 43 is achieved. The connecting rod 41 through which motion is imparted to the movable platen 48 is provided with a cam 94 which engages a switch 95 controlling a circuit 536. The circuit 85 is a secondary energizing circuit with respect to the circuit 69 which also energizes the solenoid 9? of the upset pilot valve 31.

It will thus be seen that the upset pilot valve 3'! is actuated twice during one operating cycle, it being remembered that it was initially operated subsequent to the operation of the sleeve positioning valve 55 to initially pass hydraulic fluid directly through the upset control valve 2? to the cylinder 33 and thus cause the rapid initial movement of the platen moving piston 4'5 which serves to close up the irregular spacing of the platen and bring the same to a predetermined start of flashing position.

The initial energization of the solenoid 9'1 and actuation of the upset pilot valve 3'! is only momentary whereupon the solenoid 9? is de-energized and is not subsequently re-energized until the conclusion of the flashing cycle or movement of the platen 38 which brings the cam 94 into engagement with the switch 95 and closes the secondary circuit 96, again energizing the solehold 9? to direct a large volume of hydraulic fluid to the cylinder =25 and hence rapidly move the piston in the upset portion of the welding cycle.

Still referring to Figure 1 of the drawings the construction and operation of the upset pilot valve Bl be seen. The solenoid ill is directly connected vi 'n piston valve 9% in the upset pilot valve The piston valve 96 is normally biased to the right by a coil spring 555 in which position heads Ell-ii and [9! block an inlet orifice i828 which is in communication with the fluid supply line heretofore referred to, and hence with a source of hydraulic fluid from the pump 54. Operation of the solenoid 9i moves the piston valve 98 to the left and establishes communication between an inlet port I s2 and an outlet port I03 which communicates with a channel I9 in the flashing and upset control valve 27 and whereby hydraulic fluid is delivered to a chamber I05 in the flashing and upset control valve Z'l adjacent a head Hit on the spool 52 so that the hydraulic fluid immediately moves the spool 52 in the sleeve 53 to the right accelerating the motion heretofore imparted thereto by the cam 58 (as heretofore described) and immediately fully opens the flashing and upset ports 86, 81 and 44 whereby a large volume of hydraulic fluid is delivered to the line 45 and the cylinder 43 which results in an immediate upsetting motion imparted to the platen 48 by the piston 48 responsive to the fluid action. Simultaneously with such action, the head as on the spool 52 is moved into fully open position with respect to the return line 49 and the inlet ports 5t, 89 and 88 so that hydraulic fluid on the opposite side of the piston it can be immediately delivered to the return line 93 and the supply tank Ill.

It Will occur to those skilled in the art that automatic timing devices can be incorporated in the controlling circuits heretofore mentioned so that the period of energization of the solenoids 12 and 9'5, respectively, can be predetermined. At such time as the upset solenoid 97 is energized, the solenoid l2 controlling the sequence starting valve 35 is de-energized permitting the spring 4 to return the piston valve 73 therein to normal position at the left hand end of the sequence starting valve 86 and opening a communication line between the inlet port '55 and a fluid channel till which communicates with a chamber [68 in the flash control valve 38 and hydraulic fluid is thereby delivered to the left hand side of a head I89 on the piston 48 so as to move the same to the right thereby resetting the cam 51 for a subsequent welding operation.

After a suitable time interval, the solenoid 9T controlling the upset pilot valve 31 is ole-energized and the spring 99 returns the valve piston 98 therein to normal position at the right hand end of the upset pilot valve 31 which closes communication between the inlet I02 and the outlet I03 thereof. Simultaneously, a port [H is placed in communication with a fluid channel H2 in the upset pilot valve 37. The fluid channel I 12 communicates with an annular chamber H3 in the flashing and upset control valve 2'! which in turn communicates by way of a port I 4 with a portion of the return line 93. It will thus be seen that hydraulic fluid in the chamber I05 is able to flow through the channels I94 and l 52 and the annular chamber H3 to the return line 93 and back to the tank 10. The spring 54 moves the spool 52 to the left to reset the valve for a subsequent welding operation and such action establishes communication between the inlet port 26 in the valve 21 with the annular chamber 83 about the cylindrical body member 82 and by way of the orifices 83 and 88 with the annular chamber 39 and the outlet port 56 so that hydraulic fluid then flows through the line 49 to the rod end of the cylinder 43 and thereby moves the piston 46 to the left to return the platen to starting position for a subsequent welding operation.

Simultaneously with the above described action, the sleeve positioning valve is die-energized, and, being spring centered, returns to inoperative position enabling the spring 64 in the head 59 to return the sleeve 53 to its initial position.

It will thus be seen that the initial advancing, flashing and upset cycle is completed automatically once the switch 68 is closed energizing the sleeve positioning valve 65.

It will thus be seen that in a complete platen advancing, flashing and upset welding cycle initial advancing movement of the platen starts immediately upon the closing of the switch 68 and the subsequent actuation of the solenoid 9! which together result in positioning the sleeve 53 for rapid by-pass of hydraulic fluid and opening of the valve piston 98 to initially move the spool 52 to permit flow of the hydraulic fluid direct to the platen moving cylinder 43. The platen 48 thus closes whatever irregular distance exists immediately and the flashing starts when the platen moving piston and rod it and M reach a predetermined point closing the switch 10 and actuating the sequence starting valve 35. Following this, the piston 40 moves to the left and moves the cam through its interconnecting linkage which directly moves the spool 52 to the right and opens the communication channels between the inlet port 26 and the orifices with the result that the movable platen it moves in the flashing portion of the welding cycle.

It will occur to those skilled in the art that the speed of the movable platen 48 increases in accordance with the presetting of the cam 5!, as heretofore described, so that a desirable completely variable flashing curve is achieved. It will also be noted that the action of the piston 43 in moving the cam 5| is controlled by the flow control valve '18 which is also variable. As the relative motion between the spool 52 and the sleeve 53 progresses, the motion of the platen 68 increases as desired in the flashing cycle.

At such time as the cam 94 on the connecting rod M through which the movable platen i8 is moved, reaches a predetermined upsetting point, the upsetting action is superimposed on the flashing action with no hesitancy. This occurs by the secondary energization of the solenoid 91 and its operation of the upset pilot valve 37 which immediately delivers fluid pressure to the chamber I55 in the valve 21 and instantly moves the spool 52 to the right to fully open the flashing orifices with respect to the annular chambers in the cylindrical body member 82. Full hydraulic pressure is thus instantly delivered to the cylinder 33 which results in the immediate upsetting action imparted the movable platen 48.

It will be obvious to those skilled in the art that a time delay mechanism may be incorporated if desired to control the length of time of the upset cycle. Alternately, the switch 95 may be manually opened to permit the upset solenoid 91 to be de-energized. At such time as the upset solenoid 9'! is energized, the starting sequence solenoid i2 is de-energized either automatically or manually which thereby permits fluid pressure to reset the piston Mi and the cam 5i. Following the conclusion of the upset cycle, the de-energization of the upset solenoid 9'! will permit the upset pilot valve Bl to reset and drain fluid from the valve 21 and thereby permit the spring 54 in the same to reset the spool 52 therein. Simultaneously, the spring 64 in the interior of the device will reset the sleeve 53 and the complete apparatus is then ready for a subsequent welding operation.

It will thus occur to those skilled in the art that the complete rapid initial advance motion, the flashing and the upsetting cycle provided by the control apparatus occurs by reason of the relative movement of the spool 52 and the sleeve 53 in the valve 2'! and that this relative movement is capable of being varied by the flashing curve control cam 5i and the setting of the flow control valve 18. The only interconnection between the movable platen 48 and the apparatus is the means actuating the switch it! and the switch 95 controlling the sequence starting valve 36 and the upset solenoid 91. The time of operation of the switch 95 is dependent on the prior operation of the apparatuswhich is imparting controlled flashing cycle motion tothe connecting rod 41 which carries the means actuating the switch 95.

It will thus be seen that the several objects of the invention are met by the hydraulic flash welder control disclosed herein.

Having thus described my invention, what I claim is: r

l. Hydraulic control apparatus for a flash welder having a normally fixed platen and a movable platen operated by a fluid pressure motor, said apparatus acting to control the movement of the movable platen prior to and during a welding cycle and comprising in combination a source of hydraulic fluid under pressure, a valve for controlling the flow of fluid from said source to said motor, said valve having two relatively movable valve elements, a secondary fluid pressure operated motor, variable motion transmitting mechanism interconnecting said secondary fluid pressure operated motor and one of said valve elements to move said element relatively to the other of said valve elements in such a manner that the movement of the platen will follow a predetermined position speed relationship during the flashing period of said cycle, a third fluid pressure operated motor for moving the other of said valve elements to initially by-pass said hydraulic fluid to bring the movable platen to starting position of said welding cycle.

2. Apparatus according to claim 1 and further including a solenoid actuated four-way valve for controlling said third fluid pressure operated motor.

3. Apparatus according to claim 1 and further including a solenoid actuated four-way valve for controlling said third fluid pressure operated motor, and limit switches on said movable platen for controlling said four-way valve.

4-. Apparatus according to claim 1 and further including a secondary metering valve controlling said secondary fluid operated motor.

5. In a hydraulic control for a flash welder having a normally fixed platen and a movable platen, means to control the movement of the movable platen prior to and during the welding cycle comprising in combination a source of hydraulic fluid under pressure, a fluid pressure operated motor for moving said movable platen, valve means for controlling the flow of fluid from said source to said motor, said valve means haiing two relatively movable valve elements, a secondary fluid pressure operated motor, a solenoid valve in communication with said source of hydraulic fluid, said secondary fluid pressure operated motor responsive in operation to opening of said solenoid valve, variable motion transmitting means interconnecting said secondary fluid pressure operated motor and one of said valve elements to move the said valve element in such manner that the movement of the platen will follow a predetermined position speed relationship during the flash period of said cycle, a third fluid pressure operated motor connected to the other one of said valve elements, a fourway solenoid valve in communication with said source of hydraulic fluid, said third fluid pressure operated motor responsive in operation to the opening and closing of said four-way solenoid valve to move the other of said valve elements in such manner that the movable platen will advance rapidly to starting position of said flashing period of said cycle.

No references cited. 

